I hope at the interview that they are being honest for a change about the criterion for FO upgrades. At my interview they were less than honest.
CAL is fixed on three years after check out to be elligable for upgrade. That is, you, if recomended, can go into the pool of pilots for upgrade. The locals in the pool will always be promoted above expat FO's. If there are only enough slots for locals, then expats will miss out.
As long as you know the rules before you start.
A company that has two B744's with double engine failures on the ground still inside three months still has a lot of other issues to deal with.